Alkylation process with recyle of hydrogen and recovery of hydrogen chloride

ABSTRACT

We provide processes, and process units for practicing the processes, comprising
         a. regenerating a used catalyst comprising an ionic liquid catalyst and a chloride, from an alkylation reactor, in a hydrogenation reactor to produce a regenerated catalyst effluent;   b. separating at least a portion of the regenerated catalyst effluent into a gas fraction comprising a hydrogen gas and into a light hydrocarbon fraction comprising a hydrogen chloride;   c. recycling at least a part of the gas fraction comprising the hydrogen gas to the hydrogenation reactor; and   d. recovering at least an amount of the light hydrocarbon fraction comprising the hydrogen chloride and recycling the at least the amount of the light hydrocarbon fraction to the alkylation reactor. The alkylation process units comprise a hydrogenation reactor, a fractionation unit, and connections for transmitting the gas fraction to the hydrogenation reactor and for transmitting the light hydrocarbon fraction to the alkylation reactor.

This application relates to co-filed applications titled, “HYDROGENRECYCLE AND HYDROGEN CHLORIDE RECOVERY IN AN ALKYLATION PROCESS” and“EXTRACTED CONJUNCT POLYMER NAPHTHA”, herein incorporated in theirentireties.

TECHNICAL FIELD

This application is directed to processes and process units for improvedhydrogen chloride recovery in an ionic liquid alkylation plant usinghydro-regeneration of the ionic liquid catalyst.

BACKGROUND

Improved alkylation processes and equipment are needed to provide moreefficient operation, including recycling of hydrogen to a hydrogenationreactor, and recovery and recycling of hydrogen chloride to analkylation reactor.

SUMMARY

This application provides an alkylation process, comprising:

-   -   a. regenerating a used catalyst comprising an ionic liquid        catalyst and a chloride, from an alkylation reactor, in a        hydrogenation reactor to produce a regenerated catalyst        effluent;    -   b. separating at least a portion of the regenerated catalyst        effluent into a gas fraction comprising a hydrogen gas and into        a light hydrocarbon fraction comprising a hydrogen chloride;    -   c. recycling at least a part of the gas fraction comprising the        hydrogen gas to the hydrogenation reactor; and    -   d. recovering at least an amount of the light hydrocarbon        fraction comprising the hydrogen chloride and recycling the at        least the amount of the light hydrocarbon fraction to the        alkylation reactor.

This application also provides an alkylation process, comprising:

-   -   a. regenerating a used catalyst comprising an ionic liquid        catalyst and a chloride, from an alkylation reactor, in a        hydrogenation reactor to produce a regenerated catalyst        effluent;    -   b. mixing a hydrocarbon extraction solvent with the regenerated        catalyst effluent to make a mixture;    -   c. separating at least a portion of the mixture into a gas        fraction comprising a hydrogen gas and into a light hydrocarbon        fraction comprising a hydrogen chloride, the hydrocarbon        extraction solvent, and a regenerated ionic liquid catalyst;    -   d. recycling at least a part of the gas fraction comprising the        hydrogen gas to the hydrogenation reactor;    -   e. recycling the regenerated ionic liquid catalyst to the        alkylation reactor; and    -   f. recovering at least an amount of the light hydrocarbon        fraction comprising the hydrogen chloride and recycling the at        least the amount of the light hydrocarbon fraction to the        alkylation reactor.

This application also provides an alkylation process, comprising:

-   -   a. regenerating a used catalyst comprising an ionic liquid        catalyst and a chloride, from an alkylation reactor, in a        hydrogenation reactor to produce a regenerated catalyst        effluent;    -   b. separating at least a portion of the regenerated catalyst        effluent into an offgas comprising a hydrogen gas and into a        separated liquid;    -   c. mixing a hydrocarbon extraction solvent with the offgas to        make a mixture;    -   d. separating the mixture into a gas fraction comprising the        hydrogen gas and into a light hydrocarbon fraction comprising a        hydrogen chloride;    -   e. recycling at least a part of the gas fraction comprising the        hydrogen gas to the hydrogenation reactor;    -   f. further separating the separated liquid, in the presence of a        conjunct polymer extraction solvent, into an extracted conjunct        polymer naphtha and an ionic liquid catalyst stream; and    -   g. recovering at least an amount of the light hydrocarbon        fraction comprising the hydrogen chloride and recycling the at        least the amount of the light hydrocarbon fraction to the        alkylation reactor.

In addition, this application also provides an alkylation process unit,comprising:

-   -   a) a hydrogenation reactor, wherein a used catalyst comprising        an ionic liquid catalyst and a chloride produces a regenerated        catalyst effluent;    -   b) a fractionation unit fluidly connected to the hydrogenation        reactor, that separates at least a portion of the regenerated        catalyst effluent into a gas fraction comprising a hydrogen gas        and into a light hydrocarbon fraction comprising a hydrogen        chloride;    -   c) a first connection between the fractionation unit and the        hydrogenation reactor for transmitting at least a part of the        gas fraction to the hydrogenation reactor; and    -   d) a second connection between the fractionation unit and an        alkylation reactor to transmit at least an amount of the light        hydrocarbon fraction to the alkylation reactor.

This application also provides an alkylation process unit, comprising:

-   -   a) a hydrogenation reactor, wherein a used catalyst comprising        an ionic liquid catalyst and a chloride produces a regenerated        catalyst effluent;    -   b) a separator, fluidly connected between the hydrogenation        reactor and a fractionation unit; wherein the separator        separates the regenerated catalyst effluent into a gas fraction        comprising a hydrogen gas and into a separated liquid; and        wherein the fractionation unit separates a hydrocarbon stream        from the separated liquid into a light hydrocarbon fraction        comprising a hydrogen chloride and an extracted conjunct polymer        naphtha;    -   c) a first connection between the separator and the        hydrogenation reactor for transmitting at least a part of the        gas fraction to the hydrogenation reactor; and    -   d) a second connection between the fractionation unit and an        alkylation reactor to transmit at least an amount of the light        hydrocarbon fraction to the alkylation reactor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an alkylation process unit with catalysthydro-regeneration, hydrogen recycle and hydrogen chloride recovery; thecomprehensive case.

FIG. 2 is a diagram of an alkylation process unit with catalysthydro-regeneration, hydrogen recycle, and hydrogen chloride removal bycaustic scrubbing; the comparison case.

FIG. 3 is a diagram of an alternative alkylation process unit withcatalyst hydro-regeneration, hydrogen recycle from a separator, andhydrogen chloride recovery.

FIG. 4 is a diagram of a second alternative alkylation process unit withcatalyst hydro-regeneration, hydrogen recycle and hydrogen chloriderecovery.

FIG. 5 is a diagram of a third alternative alkylation process unit withcatalyst hydrogenation, hydrogen recycle and hydrogen chloride recovery.This diagram includes a selective olefin isomerization reactor.

FIG. 6 is a diagram of a hydro-regeneration process without hydrocarbonextraction solvent.

DETAILED DESCRIPTION

Alkylation processes and alkylation process units are used to makealkylate products, including alkylated aromatics and alkylatedisoparaffins. The alkylate products can have a broad range of usesincluding, for example, gasoline blending components, middledistillates, base oils, and petrochemical components. The catalysts usedin these processes for alkylation comprise ionic liquid catalyst and achloride. These catalysts become deactivated during use and requireregeneration. The deactivation is at least in part caused by thebuild-up of conjunct polymer in the ionic liquid catalyst. Regenerationis achieved in a hydrogenation reactor (also referred to herein as ahydro-regeneration reactor). The regenerating removes the conjunctpolymer from the ionic liquid catalyst, thus increasing the acidity andability of the ionic liquid catalyst to perform alkylations.

Since the hydrogenation process uses excess amounts of hydrogen gas, itis highly desirable to be able to recycle the hydrogen gas to thehydrogenation reactor in order to minimize the hydrogen consumption. Tomaintain good performance of the hydrogenation reactor, the recycledhydrogen gas needs to have high purity, with only a small amount oflight hydrocarbons, hydrogen chloride, and other impurities.

In one embodiment, because the used catalyst includes achloride-containing conjunct polymer, the hydrogenation unit liberateshydrogen chloride, which can build up to excessive levels upon recyclingand can suppress conversion in the hydrogenation reactor unless it isremoved. Conventional acid gas treating methods, for example, causticaqueous scrubbing systems, can be used to remove the hydrogen chloride,but then the hydrogen chloride cannot be simply reused in the alkylationprocess. A comparative example of how an acid gas treating method couldbe employed in an alkylation plant shown in FIG. 2. When the hydrogengas containing hydrogen chloride (offgas (50)) is treated with causticsolution, then the hydrogen chloride is converted to a salt that cannotbe reused in the alkylation process. For example, if NaOH is used as thecaustic reactant, then the HCl is converted to NaCl and water, and theNaCl is not suitable for recycling into an ionic liquid alkylationprocess. The HCl destroyed in the HCl removal step represents asignificant operating cost since it must be compensated for byadditional chloride injection into the alkylation unit. It also resultsin an aqueous waste stream that must be neutralized and disposed of inthe water treatment system of the facility. Further, the recyclehydrogen must then be thoroughly dried before use in the hydrogenationreactor. In addition, a significant amount of a recycle gas purge (15)out of the gas fraction comprising the hydrogen gas (20) is needed inorder to suppress build up of light hydrocarbons in the recycled gas.

We provide at least four different process configurations in FIGS. 1, 3,4, and 5, where we can produce a high purity hydrogen gas stream torecycle to the hydrogenation reactor and we can recover and recyclehydrogen chloride to the alkylation reactor. The separation and recycleof hydrogen and the separation, recovery, and recycle of the hydrogenchloride are well integrated with the entire alkylation process to makethe process more efficient and economical.

Referring to FIG. 1, it is shown that a hydrogenation reactor (100) canbe used continuously with highly efficient hydrogen and hydrogenchloride use in an alkylation process employing an ionic liquid catalystand a chloride by the following process:

A used catalyst (70) comprising an ionic liquid catalyst and a chlorideis regenerated in a hydrogenation reactor (100). The used catalyst (70)is taken from an effluent (40) from the alkylation reactor (300), whichis then separated into the used catalyst (70) and the alkylate products(80). The hydrogenation reactor produces a regenerated catalyst effluent(10) which is separated in a separator (400) into an offgas (50) and anionic liquid catalyst stream (60). The ionic liquid catalyst stream (60)is recycled to the alkylation reactor (300). The offgas (50), which is aportion of the regenerated catalyst effluent (10), is separated in afractionation unit (200) into a gas fraction comprising a hydrogen gas(20) and a light hydrocarbon fraction comprising a hydrogen chloride(30). At least a part of the gas fraction comprising hydrogen gas (20)is recycled to the hydrogenation reactor (100) and at least an amount ofthe light hydrocarbon fraction comprising hydrogen chloride (30) isrecovered and recycled to the alkylation reactor (300).

The term ‘offgas’ is defined herein as a gaseous effluent from thehydrogenation reactor. ‘Recycling’ is defined herein as returningmaterial to a previous stage in a cyclic process. ‘Recovering’ isdefined herein as retaining either in a substantial amount or in full,as opposed to disposing or removing. A substantial amount is at least 50wt %.

FIG. 2 shows a comparison process unit that does not recover a lightfraction comprising a hydrogen chloride. In FIG. 2, hydrogen (90), andused catalyst (70) from an alkylation reactor (300) are regenerated in ahydrogenation reactor. The regenerated catalyst effluent (10) isseparated in a separator (400) that is a gas/liquid separation unit. Theoffgas (50) from the separator is subsequently treated in a caustictreating unit (600) and a drier (700), which remove the hydrogenchloride (as opposed to recovering) to produce a dry gas fractioncomprising a hydrogen gas (20). The gas fraction comprising the hydrogengas (20) is sent to the hydrogenation reactor. A recycle gas purge (15)stream removes excess hydrogen and light hydrocarbons from the processunit. The separated liquid (85) from the separator is mixed with ahydrocarbon extraction solvent (25) and the mixture is fed to an ionicliquid catalyst and hydrocarbon separator (500) which separates themixture into a stream comprising mixed conjunct polymer and extractionsolvent (35) and an ionic liquid catalyst stream (60). The streamcomprising mixed conjunct polymer and extraction solvent (35) is sent tothe refinery hydrocarbon pool of alkylate products (80). The ionicliquid catalyst stream (60) is recycled to the alkylation reactor (300).Chloride addition (95) is needed to replace the hydrogen chloride thatis removed in the caustic treating unit (600).

FIG. 3 shows an improved process compared to FIG. 2, wherein hydrogen isrecycled and hydrogen chloride is recovered and recycled efficiently. InFIG. 3, hydrogen (90), and used catalyst (70) from an alkylation reactor(300) are regenerated in a hydrogenation reactor. The regeneratedcatalyst effluent (10) is separated in a separator (400) that is agas/liquid separation unit. A hydrocarbon extraction solvent (25) is fedto the separator (400) such that the separator (400) produces aseparated liquid (85) and a gas fraction comprising a hydrogen gas (20).The gas fraction comprising the hydrogen gas (20) has a reduced amountof hydrogen chloride and the gas fraction comprising the hydrogen gas(20) is recycled to the hydrogenation reactor (100). The separatedliquid (85) from the separator (400) comprises a hydrogen chloride. Theseparated liquid (85) is fed to an ionic liquid catalyst and hydrocarbonseparator (500), which separates the separated liquid (85) into ahydrocarbon stream (52) and an ionic liquid catalyst stream (60). Thehydrocarbon stream (52) is fed to a fractionation unit (200), where itis separated into two streams. One stream is a light hydrocarbonfraction comprising the hydrogen chloride (30). The second stream isextracted conjunct polymer naphtha (45). The light hydrocarbon fractioncomprising the hydrogen chloride (30) is also recycled to the alkylationreactor (300). In this process the hydrogen chloride is recovered andrecycled, rather than removed, as in FIG. 2. The extracted conjunctpolymer naphtha (45) is sent to the refinery hydrocarbon pool ofalkylate products (80).

FIG. 4 shows an alternative process wherein hydrogen is recycled andhydrogen chloride is recovered and recycled. In FIG. 4, hydrogen (90),and used catalyst (70) from an alkylation reactor (300) are fed to ahydrogenation reactor (100). The regenerated catalyst effluent (10) fromthe hydrogenation reactor (100) is fed to a separator (400), whichseparates the regenerated catalyst effluent (10) into an offgas (50) anda separated liquid (85). The offgas (50) is fed to a fractionation unit(200). A hydrocarbon extraction solvent (e.g., an isoparaffin feed tothe alkylation reactor) is also fed to the fractionation unit (200). Thefractionation unit (200) separates the offgas (50) into a gas fractioncomprising the hydrogen gas (20) and a light hydrocarbon fractioncomprising a hydrogen chloride (30). The gas fraction comprising thehydrogen gas (20) is recycled to the hydrogenation reactor (100). Thelight hydrocarbon fraction comprising the hydrogen chloride (30) isrecovered and recycled to the alkylation reactor. The separated liquid(85) from the separator (400) is mixed with a conjunct polymerextraction solvent (55) and the mixture is fed to an ionic liquidcatalyst and hydrocarbon separator (500). The ionic liquid catalyst andhydrocarbon separator (500) separates the mixture of the separatedliquid (85) and conjunct polymer extraction solvent (55) into extractedconjunct polymer naphtha (45) and an ionic liquid catalyst stream (60).The extracted conjunct polymer naphtha (45) is sent to the refineryhydrocarbon pool of alkylate products (80). The ionic liquid catalyststream is recycled to the alkylation reactor (300).

FIG. 5 shows another alternative process wherein hydrogen is recycledand hydrogen chloride is recovered and recycled. In FIG. 5, a usedcatalyst (70) from an alkylation reactor (300) and optionally, hydrogen(90) are fed to a hydrogenation reactor (100). The regenerated catalysteffluent (10) from the hydrogenation reactor (100) is fed to a separator(400), which separates the regenerated catalyst effluent (10) into anoffgas (50) and a separated liquid (85). In one embodiment, hydrogen(90) is not separately fed to the hydrogenation reactor (100), as all ofthe hydrogen needs for hydrogenation are supplied by a gas fractioncomprising a hydrogen gas (20) from a fractionation unit (200). Theoffgas (50) is fed to the fractionation unit (200). Hydrogen (90) and anolefin feed (75) (e.g., 1-butene) are fed to a selective olefinisomerization reactor (800), wherein the olefin feed (75) is convertedto isomerized olefins (12) (e.g., 2-butene). A hydrocarbon extractionsolvent (25) (e.g., an isoparaffin feed (65) to be alkylated in thealkylation reactor) is mixed with the isomerized olefins (12) and themixture is fed to the fractionation unit (200). The fractionation unit(200) fractionates the offgas (50) into a gas fraction comprising thehydrogen gas (20) and a light hydrocarbon fraction comprising a hydrogenchloride (30). The gas fraction comprising the hydrogen gas (20) isrecycled to the hydrogenation reactor (100). Excess hydrogen and lighthydrocarbons are removed in a recycle gas purge (15). The lighthydrocarbon fraction comprising the hydrogen chloride (30) is recoveredand recycled to the alkylation reactor. The separated liquid (85) fromthe separator (400) can be mixed with a conjunct polymer extractionsolvent (55) or an effluent (40) from an alkylation reactor (300), (asshown), and the mixture is fed to an ionic liquid catalyst andhydrocarbon separator (500). The ionic liquid catalyst and hydrocarbonseparator (500) separates the mixture of the separated liquid (85) andone or more of conjunct polymer extraction solvent (55) and effluent(40) from an alkylation reactor (300) into a stream comprised ofextracted conjunct polymer naphtha (45) and an ionic liquid catalyststream (60). The extracted conjunct polymer naphtha (45) is sent to therefinery hydrocarbon pool of alkylate products (80). The ionic liquidcatalyst stream (60) is recycled to the alkylation reactor (300). Asneeded, chloride addition (95) can be made to the alkylation reactor(300).

Hydrogenation

The used catalyst is regenerated in the hydrogenation reactor. Thehydrogenation reactor contacts the used catalyst with hydrogen and ahydrogenation catalyst to regenerate the ionic liquid catalyst. In oneembodiment, zeolites or molecular sieves are added to the hydrogenationcatalyst to improve the catalyst's performance. In one embodiment, thehydrogenation catalyst is supported. Typical support materials for thehydrogenation catalyst are kieselguhr, alumina, silica, andsilica-alumina. Other support materials include alumina-boria,silica-alumina-magnesia, silica-alumina-titania and materials obtainedby adding zeolites and other complex oxides thereto. When used, thesupport material has adequate mechanical strength and chemical stabilityat the hydrogenation reaction temperature.

In one embodiment, the hydrogenation is carried out in the presence of acatalyst which usually comprises a metal or non metal hydrogenationcomponent on a porous support material, such as a natural clay or asynthetic oxide. Examples of metal hydrogenation components that can beused are Fe, Co, Ni, Ru, Rh, Pd, Pt, Ir, Os, Cr, Mn, Ti, V, Zr, Mo, W,and mixtures thereof. Examples of non metal hydrogenation components areTe, As, and mixtures thereof. The hydrogenation components can be usedsingly or in combination.

The hydrogenation can be carried out over a broad range of hydrogenpressures, typically from about 50 to 5,000 psig. Hydrogenationconditions can include temperatures of −20° C. to 400° C., or 50° C. to300° C.; and total pressures of atmospheric to 5,000 psig, or 50 to2,500 psig. Hydrogenation contact times can be from 0.1 minute to 24hours, such as 10 minutes to 12 hours. Feed to catalyst ratios duringthe hydrogenation can vary from 0.1 to 10 vol/vol/hour. A normalhydrocarbon can optionally be used as a solvent in the hydrogenationreactor. Examples of hydrogenation of ionic liquid catalysts forregeneration, for example, are given in U.S. Pat. No. 7,691,771, U.S.Pat. No. 7,651,970, U.S. Pat. No. 7,678,727, and U.S. Pat. No.7,825,055.

Separator for Regenerated Catalyst Effluent

In one embodiment, the separator (400) separates the regeneratedcatalyst effluent streams for efficient downstream processing. Theseparator can be configured in several different ways. For example, inFIG. 1, the separator separates the ionic liquid catalyst stream (60)from the regenerated catalyst effluent first. Then the offgas (50)stream containing hydrogen, hydrogen chloride, and hydrocarbon is sentto a fractionation unit (200) for further separation into a gas fractioncomprising a hydrogen gas (20) and a light hydrocarbon fractioncomprising a hydrogen chloride (30). In FIGS. 2, 4, and 5, the separatorseparates the regenerated catalyst effluent streams into an offgas (50)comprising hydrogen chloride gas and into a separated liquid (85). InFIG. 3, a hydrocarbon extraction solvent (25) was added to the separatorto facilitate extraction of hydrogen chloride into a liquid stream. Theseparator (400) produces a gas fraction comprising a hydrogen gas (20),having a reduced level of hydrogen chloride, and a separated liquid(85). The separated liquid (85), comprising hydrogen chloride,hydrocarbon and ionic liquid catalyst, is sent to an ionic liquidcatalyst and hydrocarbon separator (500).

Hydrocarbon Extraction Solvent

In one embodiment, the hydrogen chloride is extracted from the offgas ofthe hydrogenation reactor using a hydrocarbon extraction solvent. Thehydrogen chloride can be extracted into the hydrocarbon extractionsolvent, which is transmitted to the alkylation reactor. This embodimentis shown in FIGS. 3 through 5. The hydrocarbon extraction solvent can beany hydrocarbon that can serve as a solvent or reactant for thealkylation process. Examples of suitable extraction solvents foralkylation processes making alkylate gasoline are isobutane, alkylategasoline, isomerized olefin, and mixtures thereof.

In one embodiment the hydrocarbon extraction solvent comprises anisomerized olefin. An example of an isomerized olefin is 2-butene.Processes for isomerizing olefins to make alkylate gasoline withimproved RON are taught in U.S. Pat. No. 7,553,999.

In one embodiment, the hydrocarbon extraction solvent (25) is added tothe hydrogenation reactor (100). In another embodiment, the hydrocarbonextraction solvent (25) is added to the regenerated catalyst effluent(10). In yet another embodiment, the hydrocarbon extraction solvent isadded to either the separator (400) or the fractionation unit (200). Inone embodiment, the hydrocarbon extraction solvent is fed into a streamselected from a regenerated catalyst effluent (10), an offgas (50) froma separator, or a combination thereof.

In FIG. 3, for example, the hydrocarbon extraction solvent is added tothe regenerated catalyst effluent (10) either in the separator or priorto separating. In one embodiment, the effluent from the hydrogenationreactor can be separated by a series of a gas/liquid separator, aliquid/liquid separator, and a fractionation unit that is a distillationcolumn. In one embodiment, the effluent from the hydrogenation reactor(100) is separated by the gas/liquid separator into: a) a gas fractioncomprising a hydrogen gas (20) and b) separated liquid (85). Theseparated liquid comprises a light hydrocarbon fraction comprising ahydrogen chloride (30). In one embodiment, the liquid/liquid separatorremoves one liquid (regenerated alkylation catalyst), which is recycledback to an alkylation reactor, from a second liquid comprising thehydrocarbon extraction solvent and hydrogen chloride. The second liquidcan be distilled in a fractionation unit into at least two streams, onebeing a portion of the light hydrocarbon fraction comprising thehydrogen chloride and the hydrocarbon extraction solvent, and the otherbeing extracted conjunct polymer naphtha. In this example, thehydrocarbon extraction solvent can also be a reactant in the alkylationreactor. In this example, the hydrocarbon extraction solvent can be usedto cool the effluent from the hydrogenation reactor.

The separating of the hydrogen gas and hydrogen chloride can beperformed in a fractionation unit that is a distillation column. Forexample, in FIG. 5, the hydrocarbon extraction solvent comprises anisoparaffin (e.g., isobutane) and isomerized olefin. In this example,the hydrocarbon extraction solvent is mixed with the offgas from thehydrogenation reactor in the fractionation unit, e.g., a distillationcolumn. In one embodiment, the isoparaffin and isomerized olefin are fedto the fractionation unit, used for the separating, at a location abovewhere the offgas of the hydrogenation reactor is fed into thefractionation unit. In other words, the hydrocarbon extraction solventis fed to the fractionation unit at a location above where the hydrogengas and the hydrogen chloride are fed to the fractionation unit. In oneembodiment, the hydrocarbon extraction solvent is fed to thefractionation unit in a counter current to the flow of offgas into thefractionation unit. In this example, and other embodiments, thehydrocarbon extraction solvent comprises an olefin and an isoparaffin.The olefin and the isoparaffin can be alkylated to make an alkylategasoline blending component. In some embodiments, the alkylationcatalyst is a chloroaluminate ionic liquid catalyst.

In one embodiment, the hydrocarbon extraction solvent comprising anolefin and an isoparaffin to be alkylated to make alkylate gasoline hasan amount of isomerized olefin that is greater than 30 wt %, greaterthan 40 wt %, greater than 50 wt %, greater than 60 wt %, or greaterthan 70 wt % of the olefin in the hydrocarbon extraction solvent. Forexample, to make high RON alkylate gasoline blending component theolefin is greater than 10 wt %, greater than 15 wt %, greater than 30 wt%, greater than 40 wt %, greater than 50 wt %, and up to 100 wt %2-butene, and the isoparaffin is isobutane.

In one embodiment, the hydrocarbon extraction solvent is fed at avol/vol ratio of the hydrocarbon extraction solvent to the ionic liquidcatalyst from 0.5 to 20.0, from 1.0 to 10.0, or from 1.5 to 5.0. Thevol/vol ratio can be selected to provide the desired level of hydrogenchloride in the gas fraction comprising a (20). The desired level ofhydrogen chloride in the gas fraction comprising the hydrogen can be anylevel at least 25 wt % lower than a level of hydrogen chloride in theregenerated catalyst effluent or offgas (50), such as less than 1,000wppm, less than 600 wppm, 500 wppm or less, less than 200 wppm, or lessthan 100 wppm. Alternatively, the vol/vol ratio can be selected toprovide the desired wt % of the hydrogen chloride produced in thehydrogenation reactor that is recovered and recycled to the alkylationreactor. In some embodiments the desired level of hydrogen chloride inthe gas fraction comprising the hydrogen is much reduced, such as atleast 50 wt % up to 99% reduced.

Reactants

In one embodiment, the at least the amount of the light hydrocarbonfraction comprising the hydrogen chloride (30) additionally comprises anisoparaffin and an olefin. This embodiment is shown, for example, inFIG. 5, where the isoparaffin (e.g., isoparaffin feed (65)) and theolefin (e.g., isomerized olefins (12)) can be hydrocarbon reactants foruse in the alkylation reactor. The reactants to be alkylated, forexample, can be an olefin and an isoparaffin or an olefin and anaromatic. In one example, the reactants comprise C₂ to C₂₀ olefins andC₄-C₂₀ isoparaffins. In one embodiment, the olefin comprises anisomerized olefin (e.g., 2-butene) and the isoparaffin comprisesisobutane.

Recycling of the Light Hydrocarbon Fraction Comprising Hydrogen Chloride

In one embodiment, the at least the amount of the light hydrocarbonfraction comprising a hydrogen chloride that is recovered is notpre-treated, other than optional separating, before recycling to thealkylation reactor. For example, the process can use no pre-treatingsystem, such as aqueous caustic, to remove excess hydrogen chloride fromthe light hydrocarbon fraction. By avoiding the use of any aqueoustreating in the process, high amounts of the hydrogen chloride can berecycled and additional drying of the feeds to the alkylation reactor isgreatly reduced or eliminated.

In one embodiment, the at least the amount of the light hydrocarbonfraction is not dried before recycling to the hydrogenation reactor.Again, this is possible, because the process does not require anyaqueous steps to remove the hydrogen chloride. This is an advantage overthe process disclosed in FIG. 2, where the hydrogen chloride is removedusing an aqueous caustic wash, and the recycled hydrogen from thehydrogen chloride removal step is wet and must be thoroughly driedbefore recycling to the hydro-regeneration reactor. If the recycledhydrogen were not dried, it would react violently with the ionic liquidcatalyst, destroy the catalyst, and potentially pose an explosionhazard.

Conjunct Polymer Extraction Solvent

In one embodiment, a conjunct polymer extraction solvent (55), forexample an isoparaffin feed is blended with a separated liquid (85) fromthe separator (400). The conjunct polymer extraction solvent can be ahydrocarbon reactant, a light hydrocarbon solvent, an alkylate gasoline,or mixtures thereof. An example of this is shown in FIG. 4.

Chloride Retention

In one embodiment, at least 80 wt % of the hydrogen chloride produced inthe hydrogenation reactor is recovered and recycled to the alkylationreactor. For example, at least 85 wt %, at least 90 wt %, at least 94 wt%, up to 98 wt % of the hydrogen chloride can be recycled. In oneembodiment, the chloride in the used catalyst is a hydrogen chlorideco-catalyst.

By recycling the chloride, the amount of the chloride that needs to beadded to the process is greatly reduced. Examples of chloride that maybe added to the process to maintain the ionic liquid catalyst activityinclude hydrogen chloride, alkyl chloride, and metal chloride. In oneexample, the chloride added to the process is n-butyl chloride ort-butyl chloride. The chloride added to the process can be added at anypoint in the process, but is usually introduced into the alkylationreactor (300) as either a separate stream, or can be mixed with theionic liquid catalyst stream (60) or the light hydrocarbon fractioncomprising the hydrogen chloride (30).

Hydrogen Recycling

The hydrogen gas is separated and recycled to the hydrogenation reactor.Recycling the hydrogen can save significant cost associated withhydrogen supply. In one embodiment, the process additionally comprisesremoving a recycle gas purge (15) from the effluent from thefractionation unit (200). In one embodiment, the recycle gas purge (15)comprises an excess of the hydrogen gas from the offgas (50) of thehydrogenation reactor. This is demonstrated in FIG. 5. The excesshydrogen from the recycle gas purge (15) can then be utilized in otherparts of an integrated refinery, stored, or used for other purposes. Theremoval of the excess hydrogen gas can eliminate concerns over excessivehydrogen in distillation column overhead systems.

In one embodiment, the process comprises compressing the recycledhydrogen gas in the gas fraction comprising the hydrogen gas (20) beforerecycling it to the hydrogenation reactor (100). The compression, whenused, can use conventional compressor equipment and piping because thegas fraction comprising a hydrogen gas contains limited amounts ofhydrogen chloride, and is thus not highly corrosive.

Separating

In one embodiment, the separating of the hydrogen gas and the hydrogenchloride from the offgas is done in a distillation column. In anotherembodiment, reactants to be alkylated in the alkylation reactor are alsofed into the distillation column used to separate the hydrogen gas andthe hydrogen chloride. This embodiment is shown in FIG. 4. The reactantscan be fed either as a mixture or separately into the distillationcolumn.

In one embodiment, the reactants are fed to the distillation column atone or more locations above where the at least the part of the gasfraction is fed to the distillation column. In one embodiment, whereinthe separating is done in a distillation column into which is fedreactants to be alkylated, the reactants can be fed to the distillationcolumn at a location above where the offgas from the hydrogenationreactor is fed to the distillation column. In one embodiment, thereactants to be alkylated, e.g., makeup isobutane and isomerized olefinsare fed either separately or combined into the distillation column.

In one embodiment, as shown in FIG. 5, the regenerated catalyst effluent(10) out of the hydrogenation reactor (100) is first separated by agas/liquid separator (400) into an offgas (50) gas stream comprisinghydrogen and hydrogen chloride and a separated liquid (85) stream. Theseparated liquid (85) is fed to a catalyst and hydrocarbon separator(500) where it is further separated into an ionic liquid catalyst stream(60) and extracted conjunct polymer naphtha (45). The offgas (50) ismixed with an isoparaffin feed (65) comprising isobutane and withisomerized olefins (12) (e.g., 2-butene) in a fractionation unit (200),where they are distilled into a gas fraction comprising a hydrogen gas(20), and a light hydrocarbon fraction comprising a hydrogen chloride(30). The light hydrocarbon fraction comprising a hydrogen chloride (30)additionally comprises the isoparaffin (e.g., isobutane), the isomerizedolefins (e.g., 2-butene), and the hydrogen chloride, and this lighthydrocarbon fraction is recycled to the alkylation reactor.

In one embodiment, the stream comprising the hydrogen chloride from thedistillation column is mixed with a recycled stream comprising a mixtureof a second hydrogen chloride and a propane, from the alkylationreactor, before recycling the mixture back into the alkylation reactor.

In one embodiment, the light hydrocarbon fraction comprising thehydrogen chloride from the distillation column also comprises isobutaneand olefins. This light hydrocarbon fraction can be mixed with arecycled stream from the ionic liquid reactor before recycling themixture back into the alkylation reactor. The recycled stream from theionic liquid reactor can, for example, comprise hydrogen chloride,propane, and isobutane.

Regenerated Catalyst Effluent

The regenerated catalyst effluent (10) can comprise regenerated ionicliquid catalyst having increased catalytic activity compared to the usedcatalyst before hydrogenation. In one embodiment, the regeneratedcatalyst effluent comprises a regenerated ionic liquid catalyst that iseventually recycled to the alkylation reactor. This embodiment is shownin all the figures. The regenerated catalyst effluent (10) alsocomprises at least the portion that is separated into the gas fractioncomprising a hydrogen gas (20) and the light hydrocarbon fractioncomprising a hydrogen chloride (30).

In one embodiment, see FIG. 3 for example, the regenerated catalysteffluent (10) is separated in a gas/liquid separator (400) to producethe gas fraction comprising the hydrogen gas (20) and a separated liquid(85) that comprises hydrogen chloride. The gas fraction comprising thehydrogen gas (20) is recycled from the gas/liquid separator (400) to thehydrogenation reactor (100). The separated liquid (85) comprising thehydrogen chloride can be separated in an ionic liquid catalyst andhydrocarbon separator (500) to produce two streams, one comprising theionic liquid catalyst stream (60) having regenerated catalyst and ahydrocarbon stream (52) comprising one or more reactants for alkylation,extracted conjunct polymer naphtha (45), and the hydrogen chloride. Thehydrocarbon stream (52) can be separated in a fractionation unit (200)(e.g., a distillation column) to produce the light hydrocarbon fractioncomprising a hydrogen chloride (30) and one or more reactants foralkylation and a heavier or bottom cut comprising extracted conjunctpolymer naphtha (45). The light hydrocarbon fraction comprising thehydrocarbon reactants and the hydrogen chloride is recycled to thealkylation reactor (300) and the heavier or bottom cut is mixed with thealkylate products (80), e.g., alkylate gasoline.

Ionic Liquid Catalyst

The ionic liquid catalyst can be any ionic liquid which works well witha chloride as a co-catalyst. The ionic liquid catalyst is an organicsalt or mixture of salts. The ionic liquid catalyst can be characterizedby the general formula Q+A−, wherein Q+ is an ammonium, phosphonium,boronium, iodonium, or sulfonium cation and A− is a negatively chargedion such as Cl⁻, Br⁻, ClO₄ ⁻, NO₃ ⁻, BF₄ ⁻, BCl₄ ⁻, PF₆ ⁻, SbF₆ ⁻, AlCl₄⁻, TaF₆ ⁻, CuCl₂ ⁻, FeCl₃ ⁻, HSO₃ ⁻, RSO₃ ⁻, SO₃CF₃ ⁻, alkyl-arylsulfonate, and benzene sulfonate (e.g., 3-sulfurtrioxyphenyl). In oneembodiment the ionic liquid catalyst is selected from those havingquaternary ammonium halides containing one or more alkyl moieties havingfrom about 1 to about 12 carbon atoms, such as, for example,trimethylamine hydrochloride, methyltributylammonium halide, orsubstituted heterocyclic ammonium halide compounds, such ashydrocarbyl-substituted-pyridinium halide compounds for example1-butylpyridinium halide, benzylpyridinium halide, orhydrocarbyl-substituted-imidazolium halides, such as for example,1-ethyl-3-methyl-imidazolium chloride.

In one embodiment, the ionic liquid catalyst is an organic salt that ishygroscopic in nature and has a tendency to attract and hold watermolecules from the surrounding environment. With these ionic liquidcatalysts, in order to maintain the integrity of the ionic liquidcatalyst and its catalytic performance, the organic salts from which theionic liquid catalyst is synthesized, are thoroughly dried before thecatalyst synthesis, and moisture-free conditions are maintained duringthe alkylation reaction.

In one embodiment the ionic liquid catalyst is selected from the groupconsisting of hydrocarbyl-substituted-pyridinium chloroaluminate,hydrocarbyl-substituted-imidazolium chloroaluminate, quaternary aminechloroaluminate, trialkyl amine hydrogen chloride chloroaluminate, alkylpyridine hydrogen chloride chloroaluminate, and mixtures thereof. Forexample, the used ionic liquid catalyst can be an acidic haloaluminateionic liquid, such as an alkyl substituted pyridinium chloroaluminate oran alkyl substituted imidazolium chloroaluminate of the general formulasA and B, respectively.

In the formulas A and B; R, R₁, R₂, and R₃ are H, methyl, ethyl, propyl,butyl, pentyl or hexyl group, X is a chloroaluminate. In anotherembodiment, R, R₁, R₂, and R₃ are methyl, ethyl, propyl, butyl, pentylor hexyl group, and X is a chloroaluminate. In one embodiment the X isAlCl₄ ⁻, Al₂Cl₇ ⁻, or Al₃Cl₁₀ ⁻. In the formulas A and B, R, R₁, R₂, andR₃ may or may not be the same. In one embodiment the ionic liquidcatalyst is N-butylpyridinium heptachlorodialuminate[Al₂Cl₇ ⁻]. In oneembodiment the ionic liquid catalyst is 1-Ethyl-3-methylimidazoliumtetrachloroaluminate [emim⁺][AlCl₄ ⁻].

Products

Alkylate products that can be produced by this process include alkylatedaromatics and alkylated isoparaffins. The alkylate products can have abroad range of uses including, for example, as gasoline blendingcomponents, middle distillates, base oils, and petrochemical components.The gasoline blending components can have excellent properties,including high RONs and low RVP. The base oils can have excellentproperties, including low pour points, low cloud points, and variedviscosity indexes and kinematic viscosities. The middle distillates canhave unique branching properties, making some of them even suitable asjet fuel. Processes for making high quality alkylate gasoline blendingcomponents are described, for example, in earlier patent publications,including U.S. Pat. No. 7,432,408, U.S. Pat. No. 7,432,409, U.S. Pat.No. 7,553,999, U.S. Pat. No. 7,732,363, and US20110230692. Processes formaking base oils are described, for example, in U.S. Pat. No. 7,569,740,U.S. Pat. No. 7,576,252, U.S. Pat. No. 8,124,821, U.S. Pat. No.8,101,809, and patent application Ser. No. 12/966,638 (filed Dec. 13,2010) and Ser. No. 12/966,738 (filed Dec. 13, 2010). Processes formaking middle distillates are described, for example, in U.S. Pat. No.7,923,593, U.S. Pat. No. 7,919,664, U.S. Pat. No. 7,955,495, and U.S.Pat. No. 7,923,594. Alkylated aromatic products and processes aredescribed in U.S. Pat. No. 7,732,651.

In one embodiment the effluent (40) from the alkylation reactorcomprises the alkylate products (80). In one embodiment, a propaneproduct, an n-butane product, and an alkylate gasoline blendingcomponent product are separated from an effluent from the alkylationreactor.

Extracted Conjunct Polymer Naphtha

In one embodiment, the process additionally comprises separating anextracted conjunct polymer naphtha (45) from an effluent from thehydrogenation reactor and blending the extracted conjunct polymernaphtha into an alkylate gasoline. The extraction of the extractedconjunct polymer naphtha (45) can be performed in a catalyst &hydrocarbon separator (500) or in a fractionation unit (200). Thehydrogenation of the conjunct polymer can improve the properties of theconjunct polymer made during the alkylation reaction such that it has asuitable boiling range and purity to be blended into high qualityalkylate gasoline. Blending the extracted conjunct polymer naphtha (45)in this way can greatly reduce waste disposal and equipment costs. Forexample, incineration, neutralization, and storage equipment can beeliminated from the alkylation process unit.

The extracted conjunct polymer naphtha (45) from the offgas of thehydrogenation reactor can have a final boiling point less than 246° C.(475° F.), such as having a boiling range distribution from 90° F. to474° F. (32° C. to 246° C.), from 95° F. to 460° F. (35° C. to 238° C.),from 100° F. to 450° F. (38 C to 232° C.), from 105° F. to 445° F. (41°C. to 229° C.), or from 110° F. to 440° F. (43° C. to 227° C.). The testmethod used for determining the boiling range distribution is ASTMD86-11b. In addition, the extracted conjunct polymer naphtha can have alow sulfur content (e.g., from 0.05 wt % to 0.5 wt %) a low brominenumber (e.g., from <1 to 5), and a low chloride content (e.g., from 5ppm to 500 ppm), even without additional treatment.

In one embodiment, the process produces unique alkylate gasolineproducts that comprise the extracted conjunct polymer naphtha (45) thathas been hydrogenated and extracted from the regenerated catalysteffluent (10). In one embodiment, the alkylate gasoline comprises theextracted conjunct polymer naphtha (45) having a boiling point less than246° C. (475° F.), and as further described above, extracted from theused catalyst (70).

Alkylation Process Unit

The alkylation process unit is one designed to conduct the processesdescribed herein. Process units performing these processes are shown inFIGS. 1, 3, 4, and 5. In one embodiment, the process unit comprises ahydrogenation reactor, a fractionation unit fluidly connected to thehydrogenation reactor, a first connection between the fractionation unitand the hydrogenation reactor for transmitting at least a part of thegas fraction comprising a hydrogen gas to the hydrogenation reactor, anda second connection between the fractionation unit and the alkylationreactor to transmit at least a amount of the light hydrocarbon fractioncomprising a hydrogen chloride to the alkylation reactor. By “fluidlyconnected” it is meant that the connection provides a conduit whereinthe contents move freely past one another and have the tendency toassume the shape of their container; a liquid or gas. In anotherembodiment, the process unit comprises: a) a hydrogenation reactor,wherein a used catalyst comprising an ionic liquid catalyst and achloride produces a regenerated catalyst effluent; b) a separator,fluidly connected to the hydrogenation reactor and a fractionation unit;wherein the separator separates the regenerated catalyst effluent into agas fraction comprising a hydrogen gas and into a separated liquid; andwherein the fractionation unit separates a hydrocarbon stream from theseparated liquid into a light hydrocarbon fraction comprising a hydrogenchloride and an extracted conjunct polymer naphtha; c) a firstconnection between the separator and the hydrogenation reactor fortransmitting at least a part of the gas fraction to the hydrogenationreactor; and d) a second connection between the fractionation unit andan alkylation reactor to transmit at least an amount of the lighthydrocarbon fraction to the alkylation reactor.

In one embodiment, the alkylation process unit additionally comprises athird connection between a product treatment unit and the secondconnection wherein the light hydrocarbon fraction is mixed with arecycled stream from the product treatment unit comprising a mixture ofa light hydrogen chloride and a propane. In one embodiment, thealkylation process unit additionally comprises a selective olefinisomerization reactor, fluidly connected to the fractionation unit,which produces isomerized olefins that are fed to the fractionationunit.

In one embodiment, as shown in FIGS. 4 and 5, the alkylation processunit comprises a separator between the hydrogenation reactor and thefractionation unit, fluidly connected to the hydrogenation reactor andthe alkylation reactor; wherein the separator separates a separatedliquid (85) that comprises a regenerated ionic liquid catalyst and anextracted conjunct polymer naphtha from an offgas (50) comprising thehydrogen gas and the hydrogen chloride. In another embodiment, thealkylation process unit additionally comprises one or more separatorsbetween the hydrogenation reactor and the fractionation unit, fluidlyconnected to the hydrogenation reactor and the alkylation reactor;wherein the one or more separators produce an offgas that is fed to thefractionation unit and also produce an ionic liquid catalyst stream thatis fed to the alkylation reactor.

In one embodiment, the alkylation process unit additionally comprises acompressor located before the hydrogenation reactor (100), thatcompresses the at least the part of the gas fraction comprising thehydrogen gas (20) before recycling the at least the part of the gasfraction to the hydrogenation reactor (100). In another embodiment, thealkylation process unit additionally comprises a compressor between thefractionation unit (200) and the hydrogenation reactor (100). Acompressor is a mechanical device that increases the pressure of a gasby reducing its volume. Examples of types of compressors arehermetically sealed, open, or semi-hermetic, centrifugal, diagonal,mixed-flow, axial-flow, reciprocating, rotary screw, rotary vane,scroll, diaphragm, and air bubble.

In one embodiment, the alkylation process unit additionally comprises athird connection between a product treatment unit and the secondconnection, wherein the light hydrocarbon fraction comprising a hydrogenchloride (30) is mixed with a recycled stream, from the producttreatment unit, comprising a mixture of a gaseous hydrogen chloride anda propane. The product treatment unit is used to separate and refine theproducts produced by the process and may include further hydrotreatmentand separation steps.

The fractionation unit (200) can be fluidly connected directly to thehydrogenation reactor (100) or indirectly via an additional separationunit, such as a gas/liquid separation unit.

An example of a liquid/liquid separator that can be used is an ionicliquid catalyst and hydrocarbon separator (500), is shown in FIGS. 3, 4,and 5.

EXAMPLES Example 1 Ionic Liquid Catalyst Comprising Anhydrous MetalHalide

Various ionic liquid catalysts made of metal halides such as AlCl₃,AlBr₃, GaCl₃, GaBr₃, InCl₃, and InBr₃ could be used for the catalyticprocesses. N-butylpyridinium chloroaluminate (C₅H₅NC₄H₉Al₂Cl₇) ionicliquid catalyst is an example used in our process. The catalyst has thefollowing composition:

Wt % Al 12.4 Wt % Cl 56.5 Wt % C 24.6 Wt % H 3.2 Wt % N 3.3

Example 2 Alkylation of C₄ Olefin and Isobutane to Make AlkylateGasoline with and without HCl Recycle

Evaluation of C₄ olefins alkylation with isobutane was performed in acontinuously stirred tank reactor using typical refinery mixed C₄ olefinfeed and isobutane. An 8:1 molar mixture of isobutane and olefin was fedto the reactor while vigorously stirring. An ionic liquid catalyst wasfed to the reactor via a second inlet port targeting to occupy 6 vol %in the reactor. A small amount of n-butyl chloride was added to produceanhydrous HCl gas. The average residence time (combined volume of feedsand catalyst) was about 4 minutes. The outlet pressure was maintained at200 psig and the reactor temperature was maintained at 95° F. (35° C.)using external cooling.

The reactor effluent was separated with a gravity separator into ahydrocarbon phase and an ionic liquid catalyst phase. The hydrocarbonstream was further separated into multiple streams: a C₃ ⁻ streamcontaining HCl, an nC₄ stream, an iC₄ stream and an alkylate gasolinestream. The alkylate product had 94 Research Octane Number and 410° F.(210° C.) end point. When the C₃ ⁻ stream containing HCl was recycled tothe alkylation reactor, we were able to lower the n-butyl chloride usageby 10% without affecting alkylate gasoline properties. This confirmedthat recovering HCl with light hydrocarbon is an effective way tocapture HCl and reuse.

Example 3 Isomerization of Olefin Feed, Alkylation, Regeneration ofIonic Liquid Catalyst by Hydrogenation and a Composition ofHydrogenation Reactor Offgas

A refinery C₃ and C₄ olefin stream from a Fluid Catalytic Cracking Unit(FCC unit) was isomerized with a Pd/Al₂O₃ catalyst at 66° C. (150° F.)and 250 psig in the presence of hydrogen to produce an isomerized C₃ andC₄ olefin feed with the composition shown in Table 1.

TABLE 1 Composition of Olefin Feed Composition Mol % Propane, C3 13.3Propylene, C3= 25.4 1-Butene, 1-C4= 2.3 2-Butene, 2-C4= 16.2Isobutylene, i-C4= 6.7 n-Butane, nC4 12.4 Isobutane, iC4 22.2 C5+ 1.6Sum 100.0

The isomerized olefin was alkylated with isobutane in a continuouslystirred tank reactor. An 8:1 molar mixture of isobutane and olefin wasfed to the reactor while vigorously stirring. An ionic liquid catalystwas fed to the reactor via a second inlet port targeting to occupy 6 vol% in the reactor. A small amount of n-butyl chloride was added toproduce anhydrous HCl gas. The average residence time (combined volumeof feeds and catalyst) was about 4 minutes. The outlet pressure wasmaintained at 200 psig and the reactor temperature was maintained at 95°F. (35° C.) using external cooling. The alkylation reactor effluent wasseparated to a hydrocarbon stream and an ionic liquid catalyst stream.The ionic liquid catalyst was recycled back to the alkylation reactorand the conjunct polymer level of the ionic liquid catalyst wasgradually increased.

Used ionic liquid catalyst containing 5 wt % conjunct polymer wasregenerated by passing the ionic liquid catalyst through a hydrogenationreactor under H₂ atmosphere. 100% pure hydrogen gas was used.Hydro-regeneration of the ionic liquid catalyst was operated at 350° F.(177° C.), 350 psig, 5000 scf H₂/bbl ionic liquid catalyst, and 0.2linear hourly space velocity (LHSV) in the presence of a hydrogenationcatalyst containing Pt and Pd. The hydrogenation reactor effluent wasseparated into offgas and separated liquid streams in a gas/liquidseparator as shown in FIG. 6. The separated liquid comprised regeneratedionic liquid catalyst and extracted conjunct polymer naphtha. At theseconditions, 80 wt % of the conjunct polymer in the ionic liquid catalystwas converted to light material and the regenerated ionic liquidcatalyst contained 1% conjunct polymer. The hydrogenation reactor offgasfrom the gas-liquid separation unit contained mostly H₂ and 6000 ppm ofHCl. The offgas also contained 95% H₂ and 5 vol % of C₃-C₆ lighthydrocarbons, while the bulk of light hydrocarbon was propane andisobutane. The purity of the hydrogen gas was dropped from 100% to 95%in one pass. In order to recycle the hydrogenation reactor offgas backto the hydrogenation unit, HCl and light hydrocarbon needed to beremoved.

This example clearly shows that it will be highly desirable to have anefficient way to remove and reuse the HCl and hydrocarbon in the offgas.By removing the HCl and hydrocarbon in the offgas, the hydrogen gas canbe recycled back to the hydrogenation reactor for repeated use. Forremoval of hydrogen chloride, a caustic treating method as shown in FIG.2, would result in substantial loss of HCl and light hydrocarbon.

The separated liquid stream from the hydrogenation unit was furtherseparated into the extracted conjunct polymer naphtha and regeneratedionic liquid catalyst. The regenerated ionic liquid catalyst wasrecycled back to the alkylation reactor for reuse.

Example 4 Improved HCl Recovery from Ionic Liquid Catalyst Hydrogenationwith Hydrocarbon Extraction Solvent

Used ionic liquid catalyst containing 4 wt % conjunct polymer from aalkylation reactor was regenerated by passing the ionic liquid catalystthrough a hydrogenation reactor under H₂ atmosphere. 100% pure hydrogengas was fed to the hydrogenation reactor. The hydrogenation reactor wasoperated at 350° F. (177° C.), 400 psig, 1500 scf H₂/bbl ionic liquidcatalyst, and 2.0 LHSV in the presence of a hydrogenation catalystcontaining Pt and Pd. The hydrogenation reactor effluent was separatedinto gas and liquid streams as shown in FIGS. 3 and 6. At theseconditions, 25 wt % of the conjunct polymer in the ionic liquid catalystwas converted to light hydrocarbon material, and the regenerated ionicliquid catalyst contained 3 wt % conjunct polymer. The hydrogenationreactor offgas from the gas-liquid separator contained mostly H₂ and1500 ppm of HCl. The offgas also contained 93 vol % H₂ and 7 vol % ofC₃-C₆ light hydrocarbons, while about 85-90 vol % of the lighthydrocarbon was propane and isobutane.

To demonstrate the concept of HCl extraction with hydrocarbon extractionsolvent, n-hexane solvent was added to the hydrogenation reactoreffluent at 2 and 4 times the volume of n-hexane to the ionic liquidcatalyst flow. Then the mixture was further separated with the sameseparator. The analysis results of the offgas stream are summarized inTable 1 below.

TABLE 2 HCl Content in Hydrogenation Offgas with Hydrocarbon ExtractionSolvent n-Hexane Flow Rate 2.0 vol/vol 4.0 vol/vol n-Hexane/ n-Hexane/Ionic liquid Ionic liquid flow to the flow to the HydrogenationHydrogenation No Reactor Reactor n-Hexane Flow Effluent Effluent HCl,ppm 1500 500 300 H2 Purity, vol % 93 94 95 C3-C6, vol % 7 6 5

As we added n-hexane solvent to the hydrogenation reactor effluent, thehydrogen chloride content in the offgas dropped from 1500 ppm to 300ppm. These results clearly suggested that the hydrogen chloride in theoffgas stream can be extracted by adding hydrocarbon extraction solvent.The above set-up was a simple single stage separator. The extraction ofthe hydrogen chloride will improve further with multi-stage separationextractor, and possibly with counter-current flows of the two feeds tothe separator.

Example 5 An Integrated Process for H₂ Recycle and HCl Recovery fromIonic Liquid Catalyst Hydrogenation

This example shows an efficient H₂ purification/HCl recovery processusing the feeds to the alkylation reactor. One embodiment is shown inFIG. 5.

The offgas (50) separated from the regenerated catalyst effluent (10)from the hydrogenation reactor (100) was mixed with isomerized olefins(12) and isoparaffin feed (65) comprising make-up isobutane in theamounts as shown in Table 3. The combined mixture was separated in afractionation unit (200) that was a distillation column to separate themixture into a) a gas fraction comprising a hydrogen gas (20), havinglow hydrogen chloride content, and b) a light hydrocarbon fractioncomprising a hydrogen chloride (30). The light hydrocarbon fractioncomprising a hydrogen chloride (30) contained the bulk (>90 wt %) ofhydrogen chloride generated by the hydrogenation of the used catalyst(70) (in this example, ionic liquid catalyst). The compositions of thehydrogen gas streams before and after the HCl extraction (i.e.,Hydrogenation Unit Offgas [offgas (50)] and Purified Gas Stream [gasfraction comprising a hydrogen gas (20)], respectively) are shown inTable 3.

The gas fraction comprising a hydrogen gas (20) (also referred to as thepurified hydrogen gas stream) was recycled back to the hydrogenationreactor (100) for regeneration of the used catalyst (70), in this case aused ionic liquid catalyst. The used ionic liquid catalyst containing 5wt % conjunct polymer was passed through the hydrogenation reactor (100)at 350° F. (177° C.), 450 psig, 5000 scf H₂/bbl ionic liquid catalystusing recycled hydrogen gas, and 0.2 weight hourly space velocity (WHSV)in the presence of a hydrogenation catalyst containing Pt and Pd. Atthese conditions, 80 wt % of the conjunct polymer in the used ionicliquid catalyst was converted to light material and the regeneratedionic liquid catalyst contained 1% conjunct polymer. The hydrogenationreactor offgas [offgas (50)] from the gas-liquid separation unit[Separator (400)] contained 6000 ppm of HCl and substantial amounts ofhydrogen and light hydrocarbon.

TABLE 3 Composition of Recycle H₂ Stream and Alkylation Reactor Feedwith Recovered HCl Purified HCl-Rich Gas Hydrocarbon Stream Feed (Light(Gas hydrocarbon Make-Up fraction fraction Hydrogenation Isobutanecomprising a comprising a Unit Offgas Isomerized (Isoparaffin hydrogenhydrogen (Offgas (50)) Olefins (12) feed (65)) gas (20)) chloride (30))Material Balance HCl, mole/day 0.605 0 0 0.024 0.581 H₂, mole/day 76 6 082 0.02 C₃ ⁼, mole/day 0 170 0 0.35 169 C₃, mole/day 12 74 44 16 113 C₄⁼, mole/day 0 215 0 0 215 iC₄, mole/day 13 165 243 22 398 nC₄, mole/day1 97 28 1 124 HCl Concentration HCl Recovery, Source — — 4% 96% wt %HCl, ppm 6000 — — 200 —

The results in Table 3 show that 96% of the hydrogen chloride from thehydro-regeneration offgas [offgas (50)] was recovered by our integratedprocess using a hydrocarbon extraction solvent (25). Thehydro-regeneration offgas [offgas (50)] had very high concentration ofhydrogen chloride, 6000 ppm. After the fractionation, the Purified GasStream [(Gas fraction comprising a hydrogen gas (20)] contains only 200ppm of HCl and the Purified Gas Stream was recycled to the hydrogenationreactor (100). This process also produced a desirable light hydrocarbonfraction comprising a hydrogen chloride (30), with little residualhydrogen, and the light hydrocarbon fraction comprising a hydrogenchloride (30) was sent to the alkylation reactor (300).

This example showed that maximum recovery of hydrogen chloride could beachieved with extensive use of hydrocarbon extraction solvent where bothmake-up isobutane and olefin alkylation feeds are used to extracthydrogen chloride from the hydrogenation offgas. The efficient recoveryand recycle of hydrogen chloride greatly lowers the operating cost andreduces the quantity of make-up HCl that needs to be added to theprocess.

Example 6 Properties of Extracted Conjunct Polymer Naphtha and a Blendwith Alkylate Gasoline

Extracted conjunct polymer naphtha (45) produced by hydro-regenerationcan be recovered and blended to alkylate gasoline, as shown in thisexample.

The separated liquid from the Example 3 was mixed with isobutaneextraction solvent and then sent to another separator to produce anionic liquid catalyst stream and a hydrocarbon stream containingconjunct polymer naphtha. The regenerated ionic liquid catalyst was sentback to the alkylation reactor. The hydrocarbon stream was sent to astripper to remove the isobutane extraction solvent, and pure, extractedconjunct polymer naphtha (45) was recovered. The extracted conjunctpolymer naphtha (45) was analyzed for its properties. The properties ofthe extracted conjunct polymer naphtha (45) are compared with alkylategasoline in Table 4. Also, a blend of 0.2 vol % extracted conjunctpolymer naphtha and 99.8% alkylate gasoline was prepared and itsproperties are summarized in Table 4, with the detailed compositionshown in Table 5.

TABLE 4 Properties of Alkylate Gasoline, Conjunct Polymer Naphtha, and aGasoline Blend Containing Alkylate and Conjunct Polymer Naphtha Blend ofAlkylate 100% Extracted Gasoline with Alkylate Conjunct Polymer ConjunctPolymer Gasoline Naphtha, As-Produced Naphtha D86 IBP, ° F. 108 114 10810%, ° F. 168 185 169 50%, ° F. 213 241 213 90%, ° F. 281 297 283 EndPoint, ° F. 396 439 401 Bromine Number <1 1 <1 Research Octane 89 74 89Number (RON) Motor Octane 86 70 85 Number (MON)

The extracted conjunct polymer naphtha had a boiling point end point of439° F. and a 90 vol % boiling point of 297° F., indicating it is in thegasoline boiling range. The conjunct polymer naphtha was fully saturatedin the hydrogenation reactor as shown by the Bromine Number of only 1.The Octane Numbers of the conjunct polymer naphtha are only slightlyworse compared to pure alkylate gasoline, but the volume used in theblending is very small and does not affect the Octane Number (either RONor MON) significantly. The properties of the blend containing 0.2 vol %extracted conjunct polymer naphtha and alkylate gasoline showed littlechange from the pure alkylate gasoline, indicating that the extractedconjunct polymer naphtha can be successfully blended to make highquality alkylate gasoline, even with no additional post-treatment.

TABLE 5 Composition of Alkylate Gasoline, Conjunct Polymer Naphtha, anda Gasoline Blend Containing Alkylate and Conjunct Polymer Naphtha AlkyProduct Polymer Compostion, wt % IL Alkylate Naphtha Blend Total C4 0.90.9 1.8 1.8 1.0 1.0 Total C5 8.0 8.0 6.2 6.2 8.2 8.2 2,2-Dimethylbutane0.0 0.2 0.0 2,3-Dimethylbutane 4.4 1.0 4.3 C6 Other 2.1 12.9 2.1 TotalC6 6.5 14.1 6.5 2,3-Dimethylpentane 11.9 0.8 11.9 2,4-Dimethylpentane12.2 0.5 12.1 223-Trimethylbutane 0.1 0.0 0.1 C7 Other 0.7 15.9 0.7Total C7 24.9 17.2 24.9 223-Trimethylpentane 1.4 0.1 1.4224-Trimethylpentane 20.1 0.7 20.1 233-Trimethylpentane 5.2 0.2 5.2234-Trimethylpentane 5.5 0.2 5.5 Dimethylhexanes 8.0 0.6 8.1 C8 Other1.1 26.3 1.0 Total C8 41.4 28.2 41.4 225-Trimethylhexane 5.3 0.4 5.4235-Trimethylhexane 0.8 0.1 0.8 244-Trimethylhexane 0.2 0.1 0.2223-Trimethylhexane 0.0 0.0 0.0 224-Trimethylhexane 0.1 3.3 0.1 C9 Other1.5 19.8 1.6 Total C9 7.9 23.6 8.0 Total C10-C12 8.9 8.9 6.0 6.0 8.6 8.6Total C12+ 1.4 1.4 2.8 2.8 1.4 1.4 sum 100.0 100.0 100.0 100.0 100.0100.0 % 224-TMP/total TMP 62 58 62 % Trimethylpentane/total C8 78 4 78 %Trimethylhexane/total C9 81 16 81

The composition of the alkylate gasoline showed that the ionic liquidcatalyst has high selectivity for C₇ and C₈ isoparaffins via directalkylation of C₃ and C₄ olefins with isobutane. The C₈ and C₉hydrocarbon species are mainly trimethyl isomers in that the percentageof trimethylpentane in total C₈ is 78 wt % and the percentage oftrimethylhexane in total C₉ is 81 wt %. Among the trimethylpentaneisomers, 2,2,4-Trimethylpentane is the most common isomer. Thepercentage of 2,2,4-Trimethylpentane relative to the total C₈trimethylpentane isomers is 62%. This value of 2,2,4-Trimethylpentanerelative to the total C₈ trimethylpentane is much higher than that ofalkylate produced by the sulfuric acid alkylation process. Sulfuricalkylation processes generally produce alkylate with 50 wt % or less of2,2,4-Trimethylpentane relative to the total C₈.

The transitional term “comprising”, which is synonymous with“including,” “containing,” or “characterized by,” is inclusive oropen-ended and does not exclude additional, unrecited elements or methodsteps. The transitional phrase “consisting of” excludes any element,step, or ingredient not specified in the claim. The transitional phrase“consisting essentially of” limits the scope of a claim to the specifiedmaterials or steps “and those that do not materially affect the basicand novel characteristic(s)” of the claimed invention.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Furthermore, all ranges disclosed herein are inclusive ofthe endpoints and are independently combinable. Whenever a numericalrange with a lower limit and an upper limit are disclosed, any numberfalling within the range is also specifically disclosed.

Any term, abbreviation or shorthand not defined is understood to havethe ordinary meaning used by a person skilled in the art at the time theapplication is filed. The singular forms “a,” “an,” and “the,” includeplural references unless expressly and unequivocally limited to oneinstance.

All of the publications, patents and patent applications cited in thisapplication are herein incorporated by reference in their entirety tothe same extent as if the disclosure of each individual publication,patent application or patent was specifically and individually indicatedto be incorporated by reference in its entirety.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. Many modifications of the exemplaryembodiments of the invention disclosed above will readily occur to thoseskilled in the art. Accordingly, the invention is to be construed asincluding all structure and methods that fall within the scope of theappended claims. Unless otherwise specified, the recitation of a genusof elements, materials or other components, from which an individualcomponent or mixture of components can be selected, is intended toinclude all possible sub-generic combinations of the listed componentsand mixtures thereof.

What is claimed is:
 1. An alkylation process, comprising: a. alkylatingreactants in an alkylation reactor (300); b. regenerating a usedcatalyst (70) comprising an ionic liquid catalyst and a chloride, fromthe alkylation reactor (300), in a hydrogenation reactor (100) toproduce a regenerated catalyst effluent (10); c. separating at least aportion of the regenerated catalyst effluent (10) into a gas fractioncomprising a hydrogen gas (20) and into a light hydrocarbon fractioncomprising a hydrogen chloride (30); d recycling at least a part of thegas fraction comprising the hydrogen gas (20) to the hydrogenationreactor (100); and e. recovering at least an amount of the lighthydrocarbon fraction comprising the hydrogen chloride (30) and recyclingthe at least the amount of the light hydrocarbon fraction to thealkylation reactor (300).
 2. An alkylation process, comprising: a.alkylating reactants in an alkylation reactor (300); b. regenerating aused catalyst (70) comprising an ionic liquid catalyst and a chloride,from the alkylation reactor (300), in a hydrogenation reactor (100) toproduce a regenerated catalyst effluent (10); c. mixing a hydrocarbonextraction solvent (25) with the regenerated catalyst effluent (10) tomake a mixture; d. separating at least a portion of the mixture into agas fraction comprising a hydrogen gas (20) and into a light hydrocarbonfraction comprising a hydrogen chloride (30), the hydrocarbon extractionsolvent (25), and a regenerated ionic liquid catalyst; e. recycling atleast a part of the gas fraction comprising the hydrogen gas (20) to thehydrogenation reactor (100); f. recycling the regenerated ionic liquidcatalyst to the alkylation reactor (300); and g. recovering at least anamount of the light hydrocarbon fraction comprising the hydrogenchloride (30) and recycling the at least the amount of the lighthydrocarbon fraction to the alkylation reactor (300).
 3. An alkylationprocess, comprising: a. alkylating reactants in an alkylation reactor(300); b. regenerating a used catalyst (70) comprising an ionic liquidcatalyst and a chloride, from the alkylation reactor (300), in ahydrogenation reactor (100) to produce a regenerated catalyst effluent(10); c. separating at least a portion of the regenerated catalysteffluent (10) into an offgas (50) comprising a hydrogen gas and into aseparated liquid (85); d. mixing a hydrocarbon extraction solvent (25)with the offgas (50) to make a mixture; e. separating the mixture into agas fraction comprising the hydrogen gas (20) and into a lighthydrocarbon fraction comprising a hydrogen chloride (30); f. recyclingat least a part of the gas fraction comprising the hydrogen gas (20) tothe hydrogenation reactor (100); g. further separating the separatedliquid (85), in a presence of a conjunct polymer extraction solvent(55), into an extracted conjunct polymer naphtha (45) and an ionicliquid catalyst stream (60); and h. recovering at least an amount of thelight hydrocarbon fraction comprising the hydrogen chloride andrecycling the at least the amount of the light hydrocarbon fraction tothe alkylation reactor (300).
 4. The alkylation process of claim 2 orclaim 3, wherein the hydrocarbon extraction solvent (25) is selectedfrom the group consisting of an isoparaffin, an alkylate gasoline, anisomerized olefin, and mixtures thereof.
 5. The alkylation process ofclaim 1, claim 2, or claim 3, wherein the at least the amount of thelight hydrocarbon fraction additionally comprises an isoparaffin and anolefin.
 6. The alkylation process of claim 1, wherein the at least theamount of the light hydrocarbon fraction is mixed with a recycled streamcomprising a mixture of a second hydrogen chloride and a propane, fromthe alkylation reactor (300).
 7. The alkylation process of claim 1,claim 2, or claim 3, wherein the at least the amount of the lighthydrocarbon fraction comprising the hydrogen chloride is notpre-treated, other than optional separating, before recycling.
 8. Thealkylation process of claim 1, claim 2, or claim 3, wherein the at leastthe part of the gas fraction comprising the hydrogen gas (20) is notdried before recycling.
 9. The alkylation process of claim 1, claim 2,or claim 3, wherein at least 80 wt % of the hydrogen chloride, producedin the hydrogenation reactor (100), is recovered and recycled to thealkylation reactor (300).
 10. The alkylation process of claim 1, claim2, or claim 3, additionally comprising: removing a recycle gas purge(15) from the at least the part of the gas fraction comprising thehydrogen gas (20) prior to its recycling.
 11. The alkylation process ofclaim 1, additionally comprising compressing the at least the part ofthe gas fraction comprising the hydrogen gas (20) before recycling theat least the part of the gas fraction to the hydrogenation reactor(100).
 12. The alkylation process of claim 1, wherein the separating isdone in a distillation column, into which is fed the reactants to bealkylated in the alkylation reactor (300).
 13. The alkylation process ofclaim 12, wherein the reactants to be alkylated in the alkylationreactor (300) comprise an olefin and an isoparaffin.
 14. The alkylationprocess of claim 13, wherein the olefin comprises 2-butene and theisoparaffin comprises isobutane.
 15. The alkylation process of claim 12,wherein the reactants are fed to the distillation column at one or morelocations above where the at least the part of the gas fraction is fedto the distillation column.
 16. The alkylation process of claim 1, claim2, or claim 3, wherein the ionic liquid catalyst is recycled to thealkylation reactor (300).
 17. The alkylation process of claim 1, orclaim 2, wherein the regenerated catalyst effluent (10) comprises anextracted conjunct polymer naphtha (45).
 18. The alkylation process ofclaim 1, claim 2, or claim 3, wherein the ionic liquid catalyst isselected from the group consisting of hydrocarbyl-substituted-pyridiniumchloroaluminate, hydrocarbyl-substituted-imidazolium chloroaluminate,quaternary amine chloroaluminate, trialkyl amine hydrogen chloridechloroaluminate, alkyl pyridine hydrogen chloride chloroaluminate, andmixtures thereof.
 19. The alkylation process of claim 1, claim 2, orclaim 3, wherein a propane product, an n-butane product, and an alkylategasoline blending component product are separated from an effluent fromthe alkylation reactor (300).
 20. An alkylation process unit,comprising: a) a hydrogenation reactor (100), wherein a used catalyst(70) comprising an ionic liquid catalyst and a chloride produces aregenerated catalyst effluent (10); b) a fractionation unit (200)fluidly connected to the hydrogenation reactor (100), that separates atleast a portion of the regenerated catalyst effluent (10) into a gasfraction comprising a hydrogen gas (20) and into a light hydrocarbonfraction comprising a hydrogen chloride (30); c) a first connectionbetween the fractionation unit (200) and the hydrogenation reactor (100)for transmitting at least a part of the gas fraction to thehydrogenation reactor (100); and d) a second connection between thefractionation unit (200) and an alkylation reactor (300) to transmit atleast an amount of the light hydrocarbon fraction to the alkylationreactor (300).
 21. An alkylation process unit, comprising: a) ahydrogenation reactor (100), wherein a used catalyst (70) comprising anionic liquid catalyst and a chloride produces a regenerated catalysteffluent (10); b) a separator (400), fluidly connected to thehydrogenation reactor (100) and a fractionation unit (200); wherein theseparator (400) separates the regenerated catalyst effluent (10) into agas fraction comprising a hydrogen gas (20) and into a separated liquid(85); and wherein the fractionation unit (200) separates a hydrocarbonstream (52) from the separated liquid (85) into a light hydrocarbonfraction comprising a hydrogen chloride and an extracted conjunctpolymer naphtha (45); c) a first connection between the separator andthe hydrogenation reactor (100) for transmitting at least a part of thegas fraction to the hydrogenation reactor (100); and d) a secondconnection between the fractionation unit (200) and an alkylationreactor (300) to transmit at least an amount of the light hydrocarbonfraction to the alkylation reactor (300).
 22. The alkylation processunit of claim 20, additionally comprising one or more separators betweenthe hydrogenation reactor (100) and the fractionation unit (200),fluidly connected to the hydrogenation reactor (100) and the alkylationreactor (300); wherein the one or more separators produce an offgas (50)that is fed to the fractionation unit (200) and also produce an ionicliquid catalyst stream (60) that is fed to the alkylation reactor (300).23. The alkylation process unit of claim 20 or claim 21, additionallycomprising a compressor located before the hydrogenation reactor (100),that compresses the at least the part of the gas fraction comprising thehydrogen gas (20) before recycling the at least the part of the gasfraction to the hydrogenation reactor (100).
 24. The alkylation processunit of claim 20, additionally comprising a third connection between aproduct treatment unit and the second connection wherein the lighthydrocarbon fraction is mixed with a recycled stream from the producttreatment unit comprising a mixture of a light hydrogen chloride and apropane.
 25. The alkylation process unit of claim 20 or 21, additionallycomprising a selective olefin isomerization reactor (800), fluidlyconnected to the fractionation unit (200), that produces isomerizedolefins (12) that are fed to the fractionation unit (200).